This invention relates to flying magnetic head assemblies, and more particularly, to such an assembly which includes a ferrite core mounted in a slider body which, with an edge of the core, forms longitudinal slots with the magnetic core constituting the center rail.
Magnetic recording systems utilizing transducers that fly on an air-bearing film over a magnetic recording disk surface have been extensively utilized. Decreasing the spacing between the transducer gap and the medium enhances system performance. U.S. Pat. Nos. 3,823,416 and 3,961,372 show magnetic head assemblies in which the ferrite core is aligned with the center rail and the slider forms two outlying rails in a three rail magnetic head assembly. IBM Technical Disclosure Bulletin, Vo. XX, No. 1, June, 1977, shows a five rail or "penta" rail, magnetic head assembly. Magnetic head assemblies of this type are used in magnetic disk drives which use the so-called "Winchester" type of head. These disk drives are high performance, high density disk drives.
"Floppy" disk drives provide lower performance at a much reduced data density on the disk. U.S. Pat. No. 3,610,837 shows a magnetic head assembly similar to those used in IBM floppy disk drives. While this patent shows a substantially rectangular head assembly, these assemblies are formed into circular "buttons" in actual use.
One of the problems encountered in these magnetic head assemblies is how to increase the output voltage while maintaining the small size which is necessary for high density operation.
The output voltage is directly related to the core efficiency which is related to the reluctance of the gap and the reluctance of the rest of the core as follows: EQU n=R.sub.g /R.sub.t
where n is the efficiency, R.sub.g is the reluctance of the gap, and R.sub.t is the reluctance of the rest of the core. Reluctance is inversely proportional to the cross-sectional area of the core. In order to decrease total reluctance, with a consequent increase in efficiency and output voltage, it is desirable to increase the cross-sectional area. However, the thickness of the core is dictated by magnetic track width and must be extremely thin. The cross-sectional area can be increased only by increasing core length. However, as core length increases, the reluctance mean path is also increased so that total reluctance remains virtually unchanged. In a conventional magnetic core where the thickness is fixed it is very difficult to increase the output voltage by changing the reluctance path.
It is an object of the present invention to provide a core for a magnetic head assembly having increased efficiency and output voltage.
Attempts have been made to shorten the length of the magnetic core. The problem of handling and mounting such short length cores is solved by bonding ceramic members to the ends thereof. However, this places glass bonds on the recording head surfaces. These glass bonds often deteriorate and result in glass particles damaging the recording surface.
It is another object of the present invention to provide a high output magnetic head core without objectionable glass bonds near the magnetic gap.
Another consideration is ease of manufacture of magnetic head assemblies. Core breakage and assembly time are significant.
It is another object of the present invention to provide a magnetic core assembly having better accuracy in core location, minimized core edge wear, reduced core breakage, and assembly time.